The invention relates to a device for impregnating a web, in particular for impregnating a web laterally guided in the width direction with a treatment of fluid.
An application device with a flat, upright channel which can be filled with treatment liquid, with a sealing arrangement of the type described initially, is actually known from DE-OS 14 60 265. However, in the known embodiment, the web is guided through the flat channel from the top to the bottom, and the squeeze rollers are arranged below the channel. They form a gore in which the treatment fluid which is squeezed off collects, and from which it is passed away laterally and brought back to a collecting tank, from which the supply tank can be refilled. This application device meets the general goal in textile technology of constantly reducing the amounts of treatment liquid in the apparatuses.
However, the arrangement of the pair of squeeze rollers below the supply tank, which is accompanied by filling of the gore with treatment liquid and the necessity of lateral sealing of the gore, is also not advantageous when viewed from the aspect of uniformly squeezing off a selectable application amount, since a certain minimum pressure is required to seal the squeeze nip towards the bottom, which is equivalent to a maximum application amount.
Devices with pairs of squeeze rollers located above the supply tank are generally known in the form of a foulard, e.g. from DE 1 078 527 and DE 1 054 048. Here, the web is passed from above into a trough which is open towards the top and contains the treatment liquid. The web is deflected upward over a deflection roller located near the bottom of the trough. After exiting from the treatment liquid in the trough, the web is squeezed by means of the pair of squeeze rollers arranged above the trough. The liquid which is squeezed off runs back into the trough via a guide surface.
Because of the presence of the deflection roller, the volume of the trough is rather large, for design reasons. It is also known to house displacement elements in the trough, but there is still a significant volume of liquid which must be stored or disposed of after the end of treatment or if the treatment liquid is changed. Careful cleaning is difficult due to the presence of the displacement elements.
Accordingly, an object of the invention is the further development of a treatment device of the type stated, in such a way that the disadvantages of gore formation are avoided.